1. Field of Invention
This invention provides a pressure selector valve including a lever operator which is capable of broader (more) controlling functions than current joy stick pressure valve controllers. While the invention has indeed a wide utility controlling pneumatic and hydraulic machine functions, it is well suited to controlling pitch, roll, and elevation of heavy equipment needing precision positioning. One example of these applications includes docking of robot machines and circuit board testing fixtures in the industry of semiconductor manufacturing equipment.
Another application example is precise positioning of heavy leaded glass windows and moving radiation shielded doors within a nuclear facility.
Another application example is elevation and tilting control of heavy manufactured products (such as military tanks or motor homes) at various process stations along a factory production line.
2. Description of Prior Art
Current joy stick controllers such as that disclosed in U.S. Pat. No. 4,404,991 granted to Cullen Sep. 20, 1983; and U.S. Pat. No. 4,296,773 granted to Harshman and Dietrich Oct. 27, 1981, use a lever and attached circular cam to selectively activate four valves arranged in one array (oriented axially to and circularly around the lever). A limitation of these joy stick controllers are that the single four valve array has limited machine control utility. For example, if these joy stick controllers were plumbed to four air bags supporting a robot, they could only control robotic tilt (pitch and roll). Additional valve control for elevation is missing.
Because pressure joy stick controllers have functional limitations, some industries do not use them at all or use them in concert with additional valves or switches thus adding to the system complexity and loss of some intuitive understanding. For example, the semiconductor industry (for precision robot docking) uses an electric joy stick controller such as that disclosed in U.S. Pat. No. 5,042,314 granted to Rytter, Boucher, and Kelley Aug. 27, 1991; and U.S. Pat. No. 4,812,802 granted to Watanabe Mar. 14, 1989, to control electric motor driven ball jacking (lifting) screws to control all three functions pitch, roll and elevation. This electric system has serious limitations for the industry. The electric jack screw actuators are very expensive, heavy, and complex. Also the jack screws are about a foot high, can not fit under the robot structure, and must be bracket mounted to the outside the robot significantly increasing the robot area footprint.
This invention solves the limitations of the electric jack screw robot docking application above. The invention provides a means to use only pneumatic controls and actuators (air bags for example) with advantages of low cost, light weight, and intuitive simplicity. The invention pneumatic system components can fit easily under the robot structure (air bags can be as thin as 0.7 inches thick). The invention pneumatics can control roll, pitch, and elevation of the robot by uniquely controlling inflating and exhausting of the four supporting air bags.
Other features and advantages of the invention will become apparent to those skilled in the art during the course of the following description.